Ground-clamp.



H. W. PLEISTER.

GROUND CLAMP.

APPLICATION FILED NOV. 3, 1910.

Patented Apr. 23, 1912.

2 SHEETS-SHEET 1.

WITNESSES COLUMBIA PLANOORAPH CO" WASHINGTON. D. C-

H. W. PLEISTER.

GROUND CLAMP.

APPLIOATION rum) NOV. 3, 1910. I

1,024,021 Patented Apr. 23, 1912.

2 SHEETS-SHEET 2.

WITNESSES INVENTOR COLUMBIA PLANOGRAPH c0..wAsH1NG1'0N, u. c.

UNITED STATES PATENT ornioni.

HENRY W. PLEISTER, OF WESTFIELD, NEW JERSEY, ASSIG-NOR T0 HENRY B. NEWHALL, 0F FLAINFIELD, NEW JERSEY.

GROUND-CLAMP.

Specification of Letters Patent.

Application filed November 3, 1910. Serial No. 590,546.

To all whom it may concern:

Be it known that I, HENRY W. PLEIsTER, a citizen of the United States, and a resident of Vestfield, in the county of Union and State of New Jersey, have invented certain new and useful Improvements in Ground- Clamps, of which the following is a specification, taken in connection with the accompanying drawings, which form a part of the same.

This invention relates to ground clamps which are used to assist in grounding a low potential circuit such for example as a telephone circuit.

In the accompanying drawings I have shown illustrative embodiments of my invention in which the same reference numerals refer to similar parts in the several figures.

Figure 1 is a perspective view of my ground clamp shown located on a pipe; Fig. 2 is a plan view of a blank from which one form of stool for my clamp is made; Fig. 3 is a plan view of one form of the key; Fig. 1 is a detail perspective view of a modified form of stool; Fig. 5 is a plan view of the blank from which the stool in Fig. 4 is made; Fig. 6 is a detail perspective view of the key used with the stool illustrated in Fig. at; Fig. 7 is a detail perspective view of a modified form of ground clamp; Fig. 8

is a side elevation of the stool shown in Fig.

7; Fig. 9 is a detail perspective view of a modified form of ground clamp; Fig. 10 is a plan view of the blank from which the stool illustrated in Fig. 9 is made; Fig. 11 is a detail side elevation of a modified form of stool; and Fig. 12 is a plan view of the key used with the modified form shown in Fig. 11. p

In grounding circuits of low potential such for example as telephone circuits, it is customary to save expense to ground the cir cuit throu h the water or sewer pipe in a house or other edifice in which the telephone is located. This is quite frequently done by soldering one end of the telephone wire to the pipe which takes a great deal of time. By using my ground clamp this soldering is avoided and in addition thereto the ground clamp can be readily and expeditiously attached to pipes, or other metallic members running into the ground, of various sizes and contours.

My ground clamp 1 consists essentially of a stool 2, a key 3 and a strap or band 1. This stool 2 is preferably made out of stamped sheet metal from a blank such as shown for example in Fig. 2 having side arms 5, 5 which are bent down parallel to each other, Fig. 1, while the intermediate ears 6 and 7 are bent up to form a bearing for the key 3, each car being provided with apertures 9 and 8, respectively, the former being preferably enlarged to permit the ready insertion of the enlarged slotting portion 10 of the key 3. The key is then inserted through the ears 6 and 7 and the strap or band- 4, preferably of metal, is placed around the water or sewer pipe, or other metallic ground member 11, its two ends 112, 112 being threaded through the slot 13 in the slotted portion 10 of the key 3. It will be apparent that by rotating the handle 14: of the key, for example in the right handed direction, the strap or band 1 will be tightened upon the pipe 11 and in this manner the ground clamp will be quickly and positively secured on the member 11 through which the circuit is to be grounded. To prevent the parts working loose I may use any suitable locking means to hold the key in its locked or adjusted position. For example, I may provide on one of the ears 6 two locking lugs 12, 12 having an opening 13 between them. After the key is wound up to an extent suflicient to. hold the ground clamp, the key is pushed laterally until the arm 14 takes into the slot 13, lying between the locking lugs 12, 12, Fig. 2. As a further means of preventing the key 3 from unwinding, I preferably form its end 15 with left-handed screw threads to cooperate with the nuts 16, 17. It is obvious that after winding the key 14: so as to hold the ground clamp in position, if from any cause it should start to unwind, the left handed screws upon the end 15 will cause the nuts 17 to bind on the ear 7 and in this manner lock it from further rotation. I preferably use these left handed screw threads in conjunction with one or more locking lugs 12, or the other locking means which will be hereinafter described. The end of the telephone wire which is to be grounded is connected to the ground clamp in any suitable manner, preferably by means of the nuts 16 and 17 In some instances I may change the stool forming for example a blank 18, Fig. 5,

having side arms 19, 19 and intermediate cars 20 and 21. The side arms are bent down substantially parallel to each other, Fig. 4 while the intermediate ears 20 and 21 are bent up forming journals for the key 22, Fig. 6. In the car 20 I form an ordinary circular bearing 23, while in the car 21, I form a non-circular bearing 24 to cooperate with the non-circular portion 25 of the key 22, Fig. 6. When the key 22 is wound upon the strap or band 4 sufficiently to cause it and the stool 18 to firmly grip the pipe or other grounded member 11, the strap is prevented from becoming unwound or loose by pressing the key 22 laterally un til its non-circular portion 25 is caused to engage with the non-circular bearing or aperture 24 in the intermediate ear 21 which will obviously prevent the rotation of the key in either direction.

In some instances it is desirable to have one end 26 of the strap or band 27 firmly held by the stool 28, Fig. 7 while the other end 29 of the strap or band is passed through the aperture 30 in the key 31, Fig. 7. A cheap and economical means to accomplish this end is to form a slot 32 in one of the side arms 33 and through this slot pass the end 26 of the band or strap, bending it down so that it will bear against the pipe or other object, which will prevent its pulling through the slot 32. In this construction I also preferably use simply one locking lug 34 formed on the car 35 of the stool 28.

In some instances I may form, a blank 36 for a stool 37 Fig. 9, each end of the blank being provided with two arms 38, 38 which are bent down to contact with the pipe 39, 39, Fig. 9, while the intermediate cars 40 and 41 are bent up to form journals for the key 42. Within the body of the stool 37 I arrange slots 4-3, 43 through which the ends 44, 44 of the strap or band 45 are passed and thence through the slot 46 in the key 42. After this key 42 has been rotated and the strap or band has been wound up, thereby firmly securing the ground clamp to the pipe 39, the key is pushed laterally until its head contacts with the locking lug 47 which will prevent it from unwinding.

Instead of the locking means described to prevent the unwinding of the key, I may provide one of the ears, forexample an car 48 of a stool 49 with a central aperture 50, Fig. 11, to form a journal for the key 51, Fig. 12, and around this central aperture form one or more apertures 52, 52 to co operate with the locking member 53 carried by the key 51. This locking member is preferably formed by bending around the end of the rod, wire or other object forming the head 54 so that it will form a plug or pin 53 which can be readily inserted within these apertures 52, 52, Fig. 11, when the key 51 is pushed laterally after the band or strap has been wound up, as will be readily understood.

Having thus described this invention in connection with several illustrative embodiments thereof to the details of which I do not desire to be limited, what is claimed as new and what it is desired to secure by Letters Patent is set forth in the appended claims:

1. A ground clamp comprising in combination a stool having downwardly extending substantially parallel arms, upwardly extending apertured ears, one of the ears being provided with one or more locking lugs, a key mounted within the cars, a band or strap, and means for connecting the band or strap to the key.

2. A ground clamp comprising in combination a stool having downwardly extending substantially parallel arms, upwardly extending apertured ears, one of the ears be ing provided with one or more locking lugs, a key provided at one end with left handed screw threads, and one or more nuts cooperating with the screw threads.

HENRY W. PLEISTER. Witnesses A. M. WILLIAMS, C. M. LYONS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

